Preparation of Dense BaTiO3 Ceramics with Submicrometer Grains by Spark Plasma Sintering

• Published in: Journal of the American Ceramic Society 1999-04, Vol.82 (4), p.939-943
• Main Authors: Takeuchi, Tomonari, Tabuchi, Mitsuharu, Kageyama, Hiroyuki, Suyama, Yoko
• Format: Article
• Language: English
• Subjects: Applied sciences; Barium titanates; Building materials. Ceramics. Glasses; Ceramic industries; Ceramics; Chemical industry and chemicals; Electrotechnical and electronic ceramics; Exact sciences and technology; Grains; Spark plasma sintering; Technical ceramics
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.1999.tb01857.x

Dense BaTiO3 ceramics consisting of submicrometer grains were prepared using the spark plasma sintering (SPS) method. Hydrothermally prepared BaTiO3 (0.1 and 0.5 µm) was used as starting powders. The powders were densified to more than similar/congruent95% of the theoretical X‐ray density by the SPS process. The average grain size of the SPS pellets was less than similar/congruent1 µm, even by sintering at 1000‐1200°C, because of the short sintering period (5 min). Cubic‐phase BaTiO3 coexisted with tetragonal BaTiO3 at room temperature in the SPS pellets, even when well‐defined tetragonal‐phase BaTiO3 powder was sintered at 1100° and 1200°C and annealed at 1000°C, signifying that the SPS process is effective for stabilizing metastable cubic phase. The measured permittivity was similar/congruent7000 at 1 kHz at room temperature for samples sintered at 1100°C and showed almost no dependence on frequency within similar/congruent100‐106 Hz; the permittivity at 1 MHz was 95% of that at 1 kHz.